Carriage For A Stretch Wrapping Machine

ABSTRACT

A stretch wrap assembly comprising a base, a turntable mounted on the base, a column on the base and a carriage movable upon the column. The carriage includes a first, second, third and fourth nip rollers and first and second pre-stretch rollers. The carriage is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, the first pre-stretch roller, the second pre-stretch roller, and the fourth nip roller and to the package. The nip rollers can be on a chassis to be able to move rotationally and laterally relative to the first pre-stretch roller and the second pre-stretch roller.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application No. 61/244,573, entitled CARRIAGE FOR A STRETCH WRAPPING MACHINE, which was filed on Sep. 22, 2009, the entire contents of which are hereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention concerns stretch wrapping machines, and more particularly relates to a carriage for a stretch wrapping machine.

SUMMARY OF THE PRESENT INVENTION

An aspect of the present invention is to provide a stretch wrap assembly comprising a base, a turntable mounted on the base, a column extending upwardly from the base, and a carriage vertically movable upon the column, with the carriage being configured to have stretch wrap thereon for wrapping a product on the turntable. The carriage includes a first nip roller, a first pre-stretch roller, a second pre-stretch roller, a second nip roller, a third nip roller and a fourth nip roller. The carriage is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package. The first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller. The first nip roller and the fourth nip roller can move rotationally and laterally relative to the first pre-stretch roller and the second pre-stretch roller, respectively. A center of rotation of the first nip roller is located on a first side of a line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the fourth nip roller is also located on the first side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the second nip roller is located on a second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the third nip roller is also located on the second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. The first and second sides are located on opposite sides to the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller.

Another aspect of the present invention is to provide a carriage for a stretch wrap machine comprising a housing including a first nip roller, a first pre-stretch roller, a second pre-stretch roller, a second nip roller, a third nip roller and a fourth nip roller. The carriage is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package. The first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller. The first nip roller and the fourth nip roller can move rotationally and laterally relative to the first pre-stretch roller and the second pre-stretch roller, respectively. A center of rotation of the first nip roller is located on a first side of a line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the fourth nip roller is also located on the first side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the second nip roller is located on a second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the third nip roller is also located on the second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. The first and second sides are located on opposite sides to the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller.

Yet another aspect of the present invention is to provide a carriage for a stretch wrap machine comprising a housing having a base portion and a chassis movable relative to the base portion between an open position and a closed engaged position. The base portion includes a first pre-stretch roller and a second pre-stretch roller thereon. The chassis has a first nip roller, a second nip roller, a third nip roller and a fourth nip roller thereon. The housing, when in the closed engaged position, is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package. When the housing is in the closed engaged position, the first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller. Centers of rotation of the first nip roller and of the second nip roller move relative to the first pre-stretch roller and centers of rotation of the third nip roller and the fourth nip roller move relative to the second pre-stretch roller, respectively, by moving the housing between the open position and the closed engaged position.

Another aspect of the present invention is to provide a carriage for a stretch wrap machine comprising a housing having a base portion and a chassis movable relative to the base portion between an open position and a closed engaged position. The base portion includes a first pre-stretch roller and a second pre-stretch roller thereon. The chassis has a first nip roller, a second nip roller, a third nip roller and a fourth nip roller thereon. The housing, when in the closed engaged position, is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package. When the housing is in the closed engaged position, the first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller. A center of rotation of the first nip roller and a center of rotation of the second nip roller rotate about a first axis while the chassis moves between the open position and the closed engaged position. A center of rotation of the third nip roller and a center of rotation of the fourth nip roller rotate about a second axis while the chassis moves between the open position and the closed engaged position.

These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a wrap machine of the present invention.

FIG. 2 is a schematic view of a carriage of the wrap machine of the present invention in a loaded (threaded) and ready to wrap position.

FIG. 3 is a schematic view of the carriage of the wrap machine of the present invention in a position between the loaded (threaded) and ready to wrap position and a loading position.

FIG. 4 is a top partial view of the carriage of the wrap machine of the present invention.

FIG. 5 is a partial front view of the carriage of the wrap machine of the present invention.

FIG. 6 is a partial side view of the carriage of the wrap machine of the present invention.

FIG. 7A is a top view of the carriage of the wrap machine of the present invention with a top housing member and rear housing member removed for clarity.

FIG. 7B is a front view of the carriage of the wrap machine of the present invention with a top housing member and rear housing member removed for clarity.

FIG. 7C is a side view of the carriage of the wrap machine of the present invention with a top housing member and rear housing member removed for clarity.

FIG. 8A is a top view of a chassis of the carriage of the present invention.

FIG. 8B is a front view of a chassis of the carriage of the present invention.

FIG. 8C is a side view of a chassis of the carriage of the present invention.

FIG. 9 includes front, top, bottom and side views of a door of the chassis of the carriage of the present invention.

FIGS. 10A and 10B are top and side views, respectively, of first links of the chassis of the carriage of the present invention.

FIGS. 11A and 11B are top and side views, respectively, of second links of the chassis of the carriage of the present invention.

FIG. 12 is a schematic view of a portion of the carriage of the wrap machine of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as orientated in FIG. 1. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

The reference number 10 (FIG. 1) generally designates a wrap machine of the present invention. The wrap machine 10 includes a base 12 having a turntable 14 mounted thereon. The wrap machine 10 further includes a column 16 having a vertically movable carriage 18 (shown schematically) located thereon. Stretch wrap 20 moves with the carriage 18. The stretch wrap 20 wraps a package 24 mounted on the turntable 14 and rotating therewith. Although not shown, the wrap machine 10 may also include a gripping and cutting device for gripping the stretch wrap 20 and cutting the stretch wrap 20 during certain portions of the process of wrapping the stretch wrap 20 about the package 24. Such gripping and cutting devices are well known to those skilled in the art.

In the illustrated example, the carriage 18 (FIG. 2) is used to prestretch the stretch wrap 20. FIG. 2 illustrates schematically prestretching components of the carriage 18 of the present invention. As illustrated in FIG. 2, the carriage 18 includes a source of the stretch wrap 20 in the form of a roll 22 of stretch wrap 20, a first nip roller 25, a first pre-stretch roller 26, a second nip roller 27, a second pre-stretch roller 30, a third nip roller 32, a fourth nip roller 33, a dancer roller 34 and a diverter roller 35. The stretch wrap 20 is threaded through the carriage 18 from the roll 22 of stretch wrap 20, around a portion of the circumference of the first nip roller 25, around a portion of the circumference of the first pre-stretch roller 26 and abutting the second nip roller 27, around a portion of the circumference of the second pre-stretch roller 30 and abutting the third nip roller 32, around a portion of the circumference of the fourth nip roller 33, around a portion of the circumference of the dancer roller 34, around a portion of the circumference of the diverter roller 35 and to the package 24. The first pre-stretch roller 26 and the second pre-stretch roller 30 are driven (rotated) at different speeds and/or have a different circumference in order to stretch the stretch wrap 20 as it passes by the first pre-stretch roller 26 and the second pre-stretch roller 30 (as is well known to those skilled in the art). The first nip roller 25 and the second nip roller 27 are configured to maintain the stretch wrap 20 against the first pre-stretch roller 26 as the stretch wrap 20 is stretched by the first pre-stretch roller 26. Likewise, the third nip roller 32 and the fourth nip roller 33 are configured to maintain the stretch wrap 20 against the second pre-stretch roller 30 as the stretch wrap 20 is stretched by the second pre-stretch roller 30. Although not shown, it is contemplated that the carriage 18 could include an idler roller that rotates freely and is positioned to maintain the stretch wrap 20 against the first pre-stretch roller 26 and the second pre-stretch roller 30.

The illustrated carriage 18 allows the first nip roller 25, the second nip roller 27, the third nip roller 32 and the fourth nip roller 33 to be spaced from the first pre-stretch roller 26 and the second pre-stretch roller 30 to allow the stretch wrap 20 to be threaded through the carriage 18. As illustrated in FIG. 3, the first nip roller 25 and the second nip roller 27 are connected to each other by top and bottom first links 41 (although only the top first link 41 is illustrated in FIGS. 2-3). The first links 41 pivot about a first pivot point 43. The first links 41 are configured to be moved along line 56. As the first pivot point 43 of the first links 41 is moved downward along line 56 as shown in FIG. 3, the first links 41 will rotate counter-clockwise such that the first nip roller 25 will move downward and to the left and the second nip roller 27 will move downward and to the right. Accordingly, the first nip roller 25 will be able to move past the first pre-stretch roller 26 to the position as shown in FIG. 3. Likewise, the third nip roller 32 and the fourth nip roller 33 are connected to each other by top and bottom second links 45 (although only the top second link 45 is illustrated in FIGS. 2-3). The second links 45 pivot about a second pivot point 47. The second links 45 are configured to be moved along line 58. As the second pivot point 47 of the second links 45 is moved downward along line 58 as shown in FIG. 3, the second links 45 will rotate clockwise such that the third nip roller 32 will move downward and to the left and the fourth nip roller 33 will move downward and to the right. Accordingly, the fourth nip roller 33 will be able to move past the second pre-stretch roller 30 to the position as shown in FIG. 3. In this configuration, the carriage 18 will be able to be loaded with the stretch wrap 20 by threading the stretch wrap through the carriage 18 (as illustrated in FIG. 3). While the illustrated embodiment only includes first links 41 and second links 45 at top and bottoms of the nip rollers, it is contemplated that only one first link 41 could be connected to a top (and not bottom) of the first nip roller 25 and the second nip roller 27 and only one second link 45 could be connected to the top (and not bottom) of the third nip roller 32 and the fourth nip roller 33.

The first nip roller 25, the second nip roller 27, the third nip roller 32, the fourth nip roller 33, the first links 41 and the second links 45 are located on a chassis to allow the first nip roller 25, the second nip roller 27, the third nip roller 32 and the fourth nip roller 33 to be moved relative to the first pre-stretch roller 26 and the second pre-stretch roller 30. However, it is contemplated that the first nip roller 25 and the second nip roller 27 could be located on individual chassis and the third nip roller 32 and the fourth nip roller 33 could be located on individual chassis to allow the first nip roller 25, the second nip roller 27, the third nip roller 32, and the fourth nip roller 33 to be moved relative to the first pre-stretch roller 26 and the second pre-stretch roller 30.

In the illustrated example, as the first pivot point 43 is moved upward along line 56 and the second pivot point 47 is moved upward along line 58, the first nip roller 25, the second nip roller 27, the third nip roller 32, the fourth nip roller 33 will return to the position in FIG. 2 (i.e., in contact with the first pre-stretch roller 26 and the second pre-stretch roller 30). As the first pivot point 43 is moved upward along line 56, the first nip roller 25 will abut the first pre-stretch roller 26, thereby forcing the first links 41 to rotate counter-clockwise. However, once the second nip roller 27 abuts a bottom (as shown in FIG. 2) of the first pre-stretch roller 26, the first links 41 will rotate clockwise about the first pre-stretch roller 26 until both the first nip roller 25 and the second nip roller 27 abut the first pre-stretch roller 26. Likewise, as the second pivot point 47 is moved upward along line 58, the fourth nip roller 33 will abut the second pre-stretch roller 30, thereby forcing the second links 45 to rotate clockwise. However, once the third nip roller 32 abuts a bottom (as shown in FIG. 2) of the second pre-stretch roller 30, the second links 45 will rotate counter-clockwise about the second pre-stretch roller 30 until both the third nip roller 32 and the fourth nip roller 33 abut the second pre-stretch roller 30.

FIGS. 4-6 illustrate an embodiment of the carriage 18 of the present invention. The carriage 18 includes a base housing 60 configured to ride on the column 16 as is well known to those skilled in the art. In the illustrated example, the base housing 60 includes a rear wall 66 having a vertical travel attachment assembly 68 configured to be located on a support within the column 16 to allow the carriage 18 to move vertically on the column 16. The base housing 60 also includes a bottom housing member 70 and a top housing member 72 connected to the rear wall 66. The first pre-stretch roller 26 and the second pre-stretch roller 30 are each connected to an axle 73 (see FIG. 5) extending between the top housing member 72 and the bottom housing member 70. The top housing member 72 and/or the bottom housing member 70 can include components for controlling the rotation of the first pre-stretch roller 26 and the second pre-stretch roller 30 to control the prestretching of the stretch wrap 20 as is well known to those skilled in the art. The bottom housing member 70 also includes a pivot pin (not shown) for pivotally connecting a chassis 64 to the base housing 60. The bottom housing member 70 can also include a pivot stop 71 for limiting pivotal movement of the chassis 64. The base housing 60 has a mandrel 62 for receiving the roll 22 of stretch wrap 20. The base housing 60 also includes the first pre-stretch roller 26, the second pre-stretch roller 30 and the dancer roller 34. The first nip roller 25, the second nip roller 27, the third nip roller 32 and the fourth nip roller 33 are connected to a chassis or door 64 (see FIGS. 8A and 8B) movable relative to the base housing 60 by extending a pivot pin (not shown) through openings 61 in pivot blocks 63 extending from a bottom of the chassis 64 to allow the chassis 64 to pivot along line 65 as illustrated in FIG. 6. In the illustrated example, the chassis 64 is pivotally connected to the base housing 60. However, it is contemplated that the chassis 64 could be slidably connected to the base housing 60 (e.g., using drawer slides) or have a vertical (instead of a horizontal) hinge.

As illustrated in FIGS. 5-8C, the chassis 64 is pivotally connected to a front of the bottom housing member 70 of the base housing 60 to allow the chassis 64 to be rotated along line 65 (see FIG. 6) relative to the base housing 60. The chassis 64 comprises a U-shaped door 74 having a top portion 76, a bottom portion 78 and a front face portion 80 extending between the top portion 76 and the bottom portion 78. The U-shaped door 74 also includes a first nip roller assembly 82 comprising the first nip roller 25, the second nip roller 27, the first links 41 and axles extending through the first nip roller 25 and the second nip roller 27 and connected to the first links 41 (to allow the first nip roller 25 and the second nip roller 27 to rotate). The U-shaped door 74 also includes a second nip roller assembly 84 comprising the third nip roller 32, the fourth nip roller 33, the second links 45 and axles extending through the third nip roller 32 and the fourth nip roller 33 and connected to the second links 45 (to allow the third nip roller 32 and the fourth nip roller 33 to rotate).

In the illustrated example, during use of the wrap machine 10 to wrap the package 24 with stretch wrap 20, the chassis 64 will be locked into position relative to the base housing 60 as illustrated in FIGS. 5-7C (and as shown schematically in FIG. 2). Furthermore, the first nip roller 25 and the second nip roller 27 will be locked into position abutting the first pre-stretch roller 26 and the third nip roller 32 and the fourth nip roller 33 will be locked into position abutting the second pre-stretch roller 30. Once the roll 22 of stretch wrap 20 is empty and the carriage 18 must be refilled with another roll 22 of stretch wrap 20, the chassis 64 must be moved to allow access to the stretch wrap 20 to be loaded (threaded) as discussed above in regard to FIG. 3.

Once the first nip roller 25 and the second nip roller 27 are moved outward as described above, the chassis 64 can be rotated about a pivot point along line 65 to allow the carriage to be loaded (threaded) as also described above in regard to FIG. 3. In order to position the chassis 64 back into position for wrapping the product 24, the chassis 64 is once again rotated about a pivot point until the chassis 64 is positioned upright again. It is contemplated that a top spring and/or a bottom spring can be connected to tops and bottoms of the first nip roller assembly and the second nip roller assembly to bias the first nip roller assembly and the second nip roller assembly to their base position (e.g., forcing the first links 41 in a clockwise direction and forcing the second links 45 in a counter-clockwise direction). It is also contemplated that a top spring and/or a bottom spring can be connected to tops and bottoms of the first nip roller assembly and the second nip roller assembly to bias the first nip roller assembly and the second nip roller assembly to their open position (e.g., forcing the first links 41 in a counter-clockwise direction and forcing the second links 45 in a clockwise direction).

In the illustrated embodiment, it is noted that when the first nip roller 25 and the fourth nip roller 33 contact the first pre-stretch roller 26 and the second pre-stretch roller 30, respectively, the point of contact is beyond the front face of the circumference of the first pre-stretch roller 26 and the second pre-stretch roller 30 as viewed from FIG. 7A (i.e., on side A of lines 200 and 202 as illustrated in FIG. 12). It is contemplated that the chassis 64 could be locked in position.

The above description is considered that of the one embodiment only. Modification of the invention will occur to those skilled in the art and to those who make or use the invention. For example, it is contemplated that the carriage 18 could include a pivoting arm 300 holding the dancer roller 34, with the arm 300 being biased by a spring 302 for keeping the dancer roller 34 taut against the stretch wrap 20 (see FIG. 7A). Moreover, it is contemplated that the second nip roller 27 could have a spacing 101 (see FIG. 7B) to allow the second nip roller 27 to clear any obstacles is it is rotated between the loading and loaded positions. Furthermore, it is contemplated that the carriage could be used in an overhead wrapping apparatus as is well known to those skilled in the art. Further, it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise. 

We claim:
 1. A stretch wrap assembly comprising: a base; a turntable mounted on the base; a column extending upwardly from the base; and a carriage vertically movable upon the column, the carriage being configured to have stretch wrap thereon for wrapping a product on the turntable; the carriage including a first nip roller, a first pre-stretch roller, a second pre-stretch roller, a second nip roller, a third nip roller and a fourth nip roller; wherein the carriage is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package; wherein the first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller; wherein the first nip roller and the fourth nip roller can move rotationally and laterally relative to the first pre-stretch roller and the second pre-stretch roller, respectively; wherein a center of rotation of the first nip roller is located on a first side of a line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller; wherein a center of rotation of the fourth nip roller is also located on the first side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller; wherein a center of rotation of the second nip roller is located on a second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller; wherein a center of rotation of the third nip roller is also located on the second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller; and wherein the first and second sides are located on opposite sides to the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller.
 2. The stretch wrap assembly of claim 1, wherein: the first pre-stretch roller and the second pre-stretch roller are configured to be rotated at different speeds in order to stretch the stretch wrap as it passes by the first pre-stretch roller and the second pre-stretch roller.
 3. The stretch wrap assembly of claim 1, wherein: the carriage further includes a dancer roller, with the carriage being configured to have stretch wrap threaded around a portion of a circumference of the dancer roller and to the package.
 4. The stretch wrap assembly of claim 1, wherein: the carriage comprises a housing having a base portion and a chassis movable relative to the base portion between an open position and a closed engaged position; the base portion including the first pre-stretch roller and the second pre-stretch roller thereon; and the chassis having the first nip roller and the second nip roller thereon.
 5. The stretch wrap assembly of claim 4, wherein: the first nip roller and the second nip roller can move laterally relative to the first pre-stretch roller and the second pre-stretch roller, respectively, by moving the housing between the open position and the closed engaged position.
 6. The stretch wrap assembly of claim 4, wherein: the center of rotation of the first nip roller and the center of rotation of the second nip roller rotate about a first axis while the chassis moves between the open position and the closed engaged position; and the center of rotation of the third nip roller and the center of rotation of the fourth nip roller rotate about a second axis while the chassis moves between the open position and the closed engaged position.
 7. The stretch wrap assembly of claim 6, wherein: the first axis and the second axis are fixed in position relative to each other.
 8. The stretch wrap assembly of claim 6, wherein: at least one first link connects the first nip roller to the second nip roller; the at least one first link having the first axis passing therethrough; at least one second link connects the third nip roller to the fourth nip roller; and the at least one second link having the second axis passing therethrough.
 9. The stretch wrap assembly of claim 1, wherein: the first pre-stretch roller and the second pre-stretch roller have different circumferences in order to stretch the stretch wrap as it passes by the first pre-stretch roller and the second pre-stretch roller.
 10. A carriage for a stretch wrap machine comprising: a housing including a first nip roller, a first pre-stretch roller, a second pre-stretch roller, a second nip roller, a third nip roller and a fourth nip roller; wherein the carriage is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package; wherein the first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller; wherein the first nip roller and the fourth nip roller can move rotationally and laterally relative to the first pre-stretch roller and the second pre-stretch roller, respectively; wherein a center of rotation of the first nip roller is located on a first side of a line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller; wherein a center of rotation of the fourth nip roller is also located on the first side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller; wherein a center of rotation of the second nip roller is located on a second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller; wherein a center of rotation of the third nip roller is also located on the second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller; and wherein the first and second sides are located on opposite sides to the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller.
 11. The carriage of claim 10, wherein: the first pre-stretch roller and the second pre-stretch roller are configured to be rotated at different speeds in order to stretch the stretch wrap as it passes by the first pre-stretch roller and the second pre-stretch roller.
 12. The carriage of claim 10, wherein: the carriage further includes a dancer roller, with the carriage being configured to have stretch wrap threaded around a portion of a circumference of the dancer roller and to the package.
 13. The carriage of claim 10, wherein: the housing has a base portion and a chassis movable relative to the base portion between an open position and a closed engaged position; the base portion includes the first pre-stretch roller and the second pre-stretch roller thereon; and the chassis has the first nip roller and the second nip roller thereon.
 14. The carriage of claim 13, wherein: the first nip roller and the second nip roller can move laterally relative to the first pre-stretch roller and the second pre-stretch roller, respectively, by moving the housing between the open position and the closed engaged position.
 15. The carriage of claim 13, wherein: the center of rotation of the first nip roller and the center of rotation of the second nip roller rotate about a first axis while the chassis moves between the open position and the closed engaged position; and the center of rotation of the third nip roller and the center of rotation of the fourth nip roller rotate about a second axis while the chassis moves between the open position and the closed engaged position.
 16. The carriage of claim 15, wherein: the first axis and the second axis are fixed in position relative to each other.
 17. The carriage of claim 15, wherein: at least one first link connects the first nip roller to the second nip roller; the at least one first link having the first axis passing therethrough; at least one second link connects the third nip roller to the fourth nip roller; and the at least one second link having the second axis passing therethrough.
 18. The carriage of claim 8, wherein: the first pre-stretch roller and the second pre-stretch roller have different circumferences in order to stretch the stretch wrap as it passes by the first pre-stretch roller and the second pre-stretch roller.
 19. A carriage for a stretch wrap machine comprising: a housing having a base portion and a chassis movable relative to the base portion between an open position and a closed engaged position; the base portion including a first pre-stretch roller and a second pre-stretch roller thereon; the chassis having a first nip roller, a second nip roller, a third nip roller and a fourth nip roller thereon; wherein the housing, when in the closed engaged position, is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package; wherein, when the housing is in the closed engaged position, the first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller; and wherein centers of rotation of the first nip roller and of the second nip roller move relative to the first pre-stretch roller and centers of rotation of the third nip roller and the fourth nip roller move relative to the second pre-stretch roller, respectively, by moving the housing between the open position and the closed engaged position.
 20. The carriage of claim 19, wherein: the first pre-stretch roller and the second pre-stretch roller are configured to be rotated at different speeds in order to stretch the stretch wrap as it passes by the first pre-stretch roller and the second pre-stretch roller.
 21. The carriage of claim 19, wherein: the chassis further includes a dancer roller, with the carriage being configured to have stretch wrap threaded around a portion of a circumference of the dancer roller and to the package.
 22. The carriage of claim 19, wherein: the center of rotation of the first nip roller and the center of rotation of the second nip roller rotate about a first axis while the chassis moves between the open position and the closed engaged position; and the center of rotation of the third nip roller and the center of rotation of the fourth nip roller rotate about a second axis while the chassis moves between the open position and the closed engaged position.
 23. The carriage of claim 22, wherein: the first axis and the second axis are fixed in position relative to each other.
 24. The carriage of claim 22, wherein: at least one first link connects the first nip roller to the second nip roller; the at least one first link having the first axis passing therethrough; at least one second link connects the third nip roller to the fourth nip roller; and the at least one second link having the second axis passing therethrough.
 25. The carriage of claim 19, wherein: the first pre-stretch roller and the second pre-stretch roller have different circumferences in order to stretch the stretch wrap as it passes by the first pre-stretch roller and the second pre-stretch roller.
 26. A carriage for a stretch wrap machine comprising: a housing having a base portion and a chassis movable relative to the base portion between an open position and a closed engaged position; the base portion including a first pre-stretch roller and a second pre-stretch roller thereon; the chassis having a first nip roller, a second nip roller, a third nip roller and a fourth nip roller thereon; wherein the housing, when in the closed engaged position, is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package; wherein, when the housing is in the closed engaged position, the first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller; wherein a center of rotation of the first nip roller and a center of rotation of the second nip roller rotate about a first axis while the chassis moves between the open position and the closed engaged position; and wherein a center of rotation of the third nip roller and a center of rotation of the fourth nip roller rotate about a second axis while the chassis moves between the open position and the closed engaged position.
 27. The carriage of claim 26, wherein: the first pre-stretch roller and the second pre-stretch roller are configured to be rotated at different speeds in order to stretch the stretch wrap as it passes by the first pre-stretch roller and the second pre-stretch roller.
 28. The carriage of claim 26, wherein: the first pre-stretch roller and the second pre-stretch roller have different circumferences in order to stretch the stretch wrap as it passes by the first pre-stretch roller and the second pre-stretch roller.
 29. The carriage of claim 26, wherein: the first axis and the second axis are fixed in position relative to each other.
 30. The carriage of claim 26, wherein: at least one first link connects the first nip roller to the second nip roller; the at least one first link having the first axis passing therethrough; at least one second link connects the third nip roller to the fourth nip roller; and the at least one second link having the second axis passing therethrough. 